Patient-specific high tibia osteotomy

ABSTRACT

A surgical method for tibia osteotomy includes attaching a patient-specific alignment guide to a corresponding surface of a tibia of a patient for whom the alignment guide is customized during a pre-operative planning stage and making a partial bone cut in the tibia through a planar slot of the alignment guide. The planar slot is oriented at a patient-specific angle relative to an anatomic axis of the patient and the angle is customized during the pre-operative planning stage. The method includes opening the bone cut to form an opening wedge, and inserting a patient-specific implantable wedge into the opening wedge.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional of U.S. application Ser. No. 12/714,023filed Feb. 26, 2010, which is a continuation-in-part of U.S. applicationSer. No. 12/571,969, filed Oct. 1, 2009, which is a continuation-in-partof U.S. application Ser. No. 12/389,901, filed Feb. 20, 2009, which is acontinuation-in-part of U.S. application Ser. No. 12/211,407, filed Sep.16, 2008, which is a continuation-in-part of U.S. application Ser. No.12/039,849, filed Feb. 29, 2008, which: (1) claims the benefit of U.S.Provisional Application No. 60/953,620, filed on Aug. 2, 2007, U.S.Provisional Application No. 60/947,813, filed on Jul. 3, 2007, U.S.Provisional Application No. 60/911,297, filed on Apr. 12, 2007, and U.S.Provisional Application No. 60/892,349, filed on Mar. 1, 2007; (2) is acontinuation-in-part U.S. application Ser. No. 11/756,057, filed on May31, 2007, which claims the benefit of U.S. Provisional Application No.60/812,694, filed on Jun. 9, 2006; (3) is a continuation-in-part of U.S.application Ser. No. 11/971,390, filed on Jan. 9, 2008, which is acontinuation-in-part of U.S. application Ser. No. 11/363,548, filed onFeb. 27, 2006; and (4) is a continuation-in-part of U.S. applicationSer. No. 12/025,414, filed on Feb. 4, 2008, which claims the benefit ofU.S. Provisional Application No. 60/953,637, filed on Aug. 2, 2007.

This application is also a continuation-in-part of U.S. application Ser.No. 12/103,834, filed Apr. 16, 2008, which claims the benefit of U.S.Provisional Application No. 60/912,178, filed Apr. 17, 2007.

This application is also a continuation-in-part of U.S. application Ser.No. 12/483,807, filed on Jun. 12, 2009, which is a continuation-in-partof U.S. application Ser. No. 12/371,096, filed on Feb. 13, 2009, whichis a continuation-in-part of U.S. application Ser. No. 12/103,824, filedon Apr. 16, 2008, which claims the benefit of U.S. ProvisionalApplication No. 60/912,178, filed on Apr. 17, 2007.

The disclosures of the above applications are incorporated herein byreference.

INTRODUCTION

Various knee osteotomies are performed to adjust or change theorientation of the tibia to correct various abnormalities caused bybirth defects, trauma, or disease. High tibial osteotomies includeopen-wedge and closed-wedge osteotomies. Various cutting instruments andtools are used to perform such high tibial osteotomies.

The present teachings provide patient patient-specific surgical kits andmethods for open-wedge or closed-wedge tibial osteotomies.

SUMMARY

The present teachings provide a surgical kit that includes apatient-specific alignment guide having a three-dimensional engagementsurface custom-made by computer imaging to conform to a correspondingportion of a patient's tibial bone. The patient-specific alignment guidedefines an elongated planar slot for guiding a blade. The planar slot isoriented at a selected angle and at a selected position relative to ananatomic axis of the patient when the engagement surface engages thecorresponding portion of the tibial bone. The selected angle andselected position are determined during a pre-operative planning stage.

The present teachings also provide a surgical kit that includes apatient-specific implantable wedge for an open-wedge osteotomy, apatient-specific fixation plate and a patient-specific alignment guide.The implantable wedge includes first and second planar surfaces defininga patient-specific wedge angle, and a patient-specific outer surfaceopposite to the straight edge. The patient-specific fixation plate has athree-dimensional patient specific engagement surface for engaging thetibia and a surface engageable with the implantable wedge. Thepatient-specific alignment guide includes an engagement surfacecustom-made by computer imaging to conform to a corresponding portion ofa patient's tibial bone. The patient-specific alignment guide defines anelongated planar slot for guiding a blade. The planar slot is orientedat a selected angle and at a selected position relative to an anatomicaxis of the patient when the engagement surface engages thecorresponding portion of the tibial bone. The selected angle andselected position are determined during a pre-operative planning stage.

The present teachings provide a surgical method including attaching apatient-specific alignment guide to a corresponding surface of a tibiaof a patient for whom the alignment guide is customized during apre-operative planning stage and making a partial bone cut in the tibiathrough a planar slot of the alignment guide. The planar slot isoriented at a patient-specific angle relative to an anatomic axis of thepatient and the angle is customized during the pre-operative planningstage. The method includes opening the bone cut to form an openingwedge, and inserting a patient-specific implantable wedge into theopening wedge.

The present teachings provide a surgical method including attaching apatient-specific alignment guide to a corresponding surface of a tibiaof a patient for whom the alignment guide is customized duringpre-operative planning and making a first partial planar cut in thetibia through a first planar slot of the alignment guide. The firstplanar slot is oriented at a first patient-specific angle relative to ananatomic axis of the patient and the first angle customized during apre-operative planning stage. A second partial planar cut is made in thetibia through a second planar slot of the alignment guide. The secondplanar slot is oriented at a second patient-specific angle relative toan anatomic axis of the patient and the second angle is customizedduring the pre-operative planning stage. The first and second planarcuts meet at an angle to define a bone wedge having a thirdpatient-specific angle. The method includes removing the bone wedge toform a wedge opening and closing the wedge opening.

Further areas of applicability of the present teachings will becomeapparent from the description provided hereinafter. It should beunderstood that the description and specific examples are intended forpurposes of illustration only and are not intended to limit the scope ofthe present teachings.

BRIEF DESCRIPTION OF THE DRAWINGS

The present teachings will become more fully understood from thedetailed description and the accompanying drawings, wherein:

FIG. 1 is a schematic illustration of a cut for open-wedge high tibialosteotomy in relation to the present teachings;

FIG. 1A is a schematic illustration of the geometry of an exemplary cutplane in relation to anatomic sagittal and transverse planes accordingto the present teachings;

FIG. 2 is a schematic illustration of opening the cut of FIG. 1 to forman wedge opening;

FIG. 3A is an environmental sectional view of a patient-specific wedgefor the wedge opening of FIG. 2 according to the present teachings;

FIG. 3B is an environmental sectional view of a patient-specific plateand a patient-specific wedge of open-wedge high tibial osteotomyaccording to the present teachings;

FIG. 4 is a schematic illustration of removing a bone wedge forclosed-wedge high tibial osteotomy in relation to the present teachings;

FIG. 5 is a schematic illustration of closing the wedge opening of FIG.4 and attaching one fixation plate;

FIG. 5A is a schematic illustration of closing the wedge opening of FIG.4 and attaching two fixation plates;

FIG. 6 is an environmental view of a patient-specific guide for anopen-wedge high tibial osteotomy in relation to the present teachings;

FIG. 7 is an environmental view of a patient-specific guide forclosed-wedge high tibial osteotomy in relation to the present teachings;

FIG. 8 is an environmental view of a patient-specific guide for anopen-wedge high tibial osteotomy in relation to the present teachings;

FIG. 9 is an environmental view of a patient-specific guide forclosed-wedge high tibial osteotomy in relation to the present teachings;

FIG. 10 is an isometric view of a patient-specific guide according topresent teachings;

FIG. 11 is an environmental view of the patient-specific guide of FIG.10 according to present teachings;

FIG. 12 is an isometric view of an exemplary implantable wedge accordingto present teachings;

FIG. 13 is an environmental view of the patient-specific wedge implantof FIG. 11 according to present teachings; and

FIGS. 14A and 14B are plan views of exemplary implantable wedgesaccording to present teachings.

DESCRIPTION OF VARIOUS ASPECTS

The following description is merely exemplary in nature and is in no wayintended to limit the present teachings, applications, or uses. Forexample, although the present teachings are illustrated forpatient-specific instruments and implants for high tibial osteotomy, thepresent teachings can be used for other types of osteotomy procedures.

The present teachings generally provide patient-specific surgical kitsthat include alignment guides and associated implant components for usein osteotomy, such as high tibial osteotomy, for example. Thepatient-specific alignment guides can be used either with conventionalor patient-specific implant components prepared with computer-assistedimage methods. Computer modeling for obtaining three dimensional imagesof the patient's anatomy using MRI or CT scans of the patient's anatomy,the patient specific prosthesis components, and the patient-specificguides and templates can be provided by various CAD programs and/orsoftware available, for example, by Materialise USA, Ann Arbor, Mich.

The patient-specific alignment guides and associated patient-specificimplants disclosed herein can be generally formed using computermodeling based on the patient's 3-D anatomic image generated from imagescans. The patient-specific alignment guides can have athree-dimensional engagement surface that is made to conforminglycontact and match a three-dimensional image of the patient's bonesurface (selectively with or without soft tissue), by the computermethods discussed above. The patient-specific alignment guides caninclude custom-made guiding formations, such as, for example, guidingbores or cannulated guiding posts or cannulated guiding extensions orreceptacles that can be used for supporting or guiding otherinstruments, such as drill guides, reamers, cutters, cutting guides andcutting blocks or for inserting pins or other fasteners according to asurgeon-approved pre-operative plan.

In various embodiments, the patient-specific alignment guide can includeone or more patient-specific cutting guides for receiving and guiding acutting blade at corresponding patient-specific cutting planeorientations relative to a selected anatomic axis for the specificpatient. The patient-specific alignment guides can also include guidingformations for guiding the implantation of patient-specific oroff-the-shelf implants associated with the osteotomy procedure, such asimplantable wedges and implantable fixation plates. The geometry, shapeand orientation of the various features of the patient-specificalignment guide, as well as various patient-specific implants and otherpatient-specific tools can be determined during the pre-operativeplanning stage of the procedure in connection with the computer-assistedmodeling of the patient's anatomy. During the pre-operative planningstage, patient-specific alignment guides, implants and other tools, canbe selected and manufactured for a specific-patient with input from asurgeon or other professional associated with the surgical procedure, asdescribed in the commonly assigned and co-pending patent applicationslisted in the cross reference section and incorporated herein byreference.

In the following discussion, the terms “patient-specific”, “custom-made”or “customized” are defined to apply to components, including tools,implants, portions or combinations thereof, which include certaingeometric features, including surfaces, curves, or other lines, andwhich are made to closely conform as mirror-images or negatives ofcorresponding geometric features of a patient's anatomy during apre-operative planning stage based on 3-D computer images of thecorresponding anatomy reconstructed from image scans of the patient bycomputer imaging methods. Further, patient specific guiding features,such as, guiding apertures and guiding slots, or other holes or openingsthat are included in alignment guides or in implants are defined asfeatures that are made to have positions, orientations, dimensions,shapes and/or define cutting planes specific to the particular patient'sanatomy based on the computer-assisted pre-operative plan associatedwith the patient.

A patient-specific osteotomy kit for an open-wedge osteotomy caninclude, according to the present teachings, a patient-specificalignment guide 200, as shown in FIG. 6, for example, a patient-specificimplantable wedge (or wedge implant) 300, as shown in FIGS. 3A-3B, forexample, and a patient-specific implantable fixation plate 400, as shownin FIG. 5, for example. The implantable wedge 300 and a patient-specificimplantable fixation plate 400 can be modularly connected, oralternatively formed monolithically as a single integral structure. Anoff-the-shelf, i.e. non patient-specific implantable wedge or anoff-the-shelf, i.e. non patient-specific implantable fixation plate canalso be used optionally with the patient-specific alignment guide 200.For closed-wedge osteotomies, the implantable wedge 300 is omitted. Itwill be appreciated that the patient-specific alignment guides foropen-wedge and closed-wedge osteotomies can include different features,as discussed below.

The patient-specific osteotomy kit can also include custom-made sawblades 500 a, 500 b having a predetermined cutting length correspondingto a patient-specific cutting depth. The cutting depth can be determinedat the pre-operative planning stage. In various embodiments, thepredetermined cutting length can be an actual dimension of the cuttingedge of the blade 500 b (see FIG. 9). In various other embodiments, thecutting depth can be adjustable and the blade 500 a can include markings502 indicating a patient-specific cutting depth. The cutting depth canalso be constrained by a depth stop engaging the patient-specificalignment guide 200 at a patient-specific depth and preventing insertionof the cutting blade beyond the pre-determined length. A separate,commercially available depth gauge can also be used to mark and restrictcutting to a pre-determined patient-specific cutting depth.

Referring to FIGS. 1 and 2, an exemplary open-wedge high tibialosteotomy is illustrated in association with a knee joint 75 between afemur 70 and a tibia 80. A planar cut 90 at a selected angle β relativeto a first reference axis A of the knee joint 75 can be made using thepatient-specific kit of the present teachings. The first reference axisA can be a selected anatomic axis, such as, for example a mechanicalaxis of the joint or leg, a mechanical axis of the femoral bone, or amechanical axis of the tibial bone, when different from the mechanicalaxis of the leg. Other anatomic axes, such as axes having significantlydifferent orientations than the orientation of axis A illustrated inFIG. 1, can be used as reference axes, including, for example, anepicondylar axis, which can be substantially transverse to the axis A ofFIG. 1. The angle β of the planar cut 90 relative to the reference axisA can be determined during the pre-operative planning stage of theosteotomy and in relation to the corresponding alignment guide 200.

The planar cut 90 can also be oriented at a patient-specific anglerelative to second and third reference axes B₁ and B₂. A representativegeometry illustrating the orientation of an exemplary cut plane P inrelation to a sagittal plane S and a transverse plane T of the patient'sanatomy is shown in FIG. 1A. In FIG. 1A, a first angle φ₁ is definedbetween an axis N perpendicular to the cut plane P and an axis zparallel to the first reference axis A, which extendsuperiorly-inferiorly on the sagittal plane. The first angle φ₁ andangle β have a sum of 90 degrees. A second angle φ₂ is defined betweenthe axis N and an axis x parallel to the second reference axis B₁, whichextends medially-laterally on the transverse plane T. A third angle φ₃is defined between the axis N and an axis y parallel to the thirdreference axis B₂, which extends anteriorly-posteriorly on thetransverse plane T. Medial-lateral, anterior-posterior andsuperior-inferior orientations of the cut plane P can be specified byselecting patient specific values for these angles, keeping in mind thatonly two of the three angles can be specified independently, while thethird can be calculated from the relation that the sum of the squares ofthe cosines of the angles is equal to 1. In the following discussion,although patient-specific orientations of planar cuts and correspondingplanar slots relative to the axis A will be described in detail, it willbe understood that the planar cuts and planar slots can be additionallyor alternatively be oriented at patient-specific angles about the axesB₁ and B₂.

Referring to FIGS. 1-3, the planar cut 90 is a partial cut, i.e., not athrough cut, and can extend from a first boundary 92 at the intersectionof the planar cut 90 with the outer surface of the tibia 80 to a secondboundary 94 at the selected patient-specific cutting depth illustratedas distance L in FIG. 1. The first boundary 92 can be generally a curvedline reflecting the curvature of the outer surface of the tibia 80. Thesecond boundary 94 can be substantially a straight line as formed by thesaw blade. The second boundary 94 can function as a hinge line (alsoreferenced with numeral 94) for opening a wedge angle γ between firstand second opposing faces 96, 98 of the cut 90, as illustrated by arrowsC in FIG. 2. The wedge angle γ is patient-specific and can be selectedduring the pre-operative planning stage. The location of the first andsecond boundaries 92, 94, the angle β of the planar cut 90 relative tothe reference axis A and the wedge angle γ can be determined during thepre-operative planning stage for correcting a condition of theparticular patient, including conditions resulting from idiopathic bonemisalignment, joint or bone disease, trauma, cancer or other therapeuticor corrective surgery. Similarly, the planar cut 90 can be oriented at acorresponding patient-specific angle φ₂ relative to the medial-lateralaxis B₁, as illustrated in FIG. 1A.

Referring to FIGS. 1-3A, a patient-specific implantable wedge 300 havinga corresponding wedge angle γ defined between first and second planarsurfaces 302, 304 can be inserted and/or pushed between the first andsecond faces 96, 98 of the cut 90, while the cut 90 is partially open,i.e., while the first and second faces 96, 98 form an angle smaller thanthe angle γ, for guiding and facilitating the correct wedge opening toform the pre-selected angle γ. It will be appreciated, however, the cut90 can be opened to an angle γ, using any other tool, such as trialwedge having the same angle γ.

With continued reference to FIGS. 1-3A, the first and second first andsecond planar surfaces 302, 304 of the implantable wedge 300 can meet ata straight edge or truncated plane surface 306. Upon insertion of theimplantable wedge 300, the cut 90 is opened and secured to the selectedangle γ by the implantable wedge 300. The first and second planarsurfaces 302, 304 of the implantable wedge 300 can abut against thefirst and second surfaces 96, 98 of the planar cut 90, and the edge 306of the implantable wedge 300 can abut the second boundary 94 of theplanar cut 90. The implantable wedge 300 can have a patient-specificboundary surface 308 opposite to the edge/surface 306. The boundarysurface 308 is designed during the pre-operative planning stage as acontinuous and smooth surface that provides a continuous contourrelative to the contour of the tibia 80 on either side of the cut 90.The implantable wedge 300 can also be secured directly in the bone withsutures, pins, anchors or other fasteners.

Alternatively, and referring to FIGS. 3A and 3B, a patient-specificimplantable fixation plate 400 can be used in combination with thepatient-specific implantable wedge 300. The patient-specific implantablewedge 300 and the patient-specific fixation plate 400 can be modularlyconnected, as illustrated in FIG. 3B, or can be provided as a singlemonolithic and integrally formed component. A modular connection caninclude a dovetail connection illustrated at reference numerals 402 and310 corresponding to opposing connection formations of the fixationplate 400 and implantable wedge 300. Other connection formations caninclude a taper lock connection, various groove and tongue connections,or connections with threadable fasteners or other biocompatiblefasteners. The modular connection can be formed at a common boundary 404between the fixation plate 400 and the implantable wedge 300.

The fixation plate 400 can include patient-specific surfaces 406 a, 406b on either side the implantable wedge 300 and can be anchored to thetibia 80 using bone pins or other bone fasteners 450 that pass throughcorresponding apertures 408 of the fixation plate 400. The location andorientation of the apertures can also be patient-specific and determinedduring the pre-operative planning stage for the particular patient.

In various embodiments, and referring to FIG. 6, a patient-specificalignment guide 200 for an open-wedge osteotomy is illustrated. Thealignment guide 200 can include a three-dimensional patient-specificengagement surface 202 made to conform to a corresponding outer surfaceof the tibia 80 by a computer-assisted method utilizing a 3-D image ofthe patient's tibia 80 during the pre-operative planning stage, asdiscussed above. The alignment guide 200 can include one or more guidingreceptacles, the precise location of which is determined on the basis ofa pre-operative surgical plan for locating alignment pins or otherfasteners or for assisting in locating cutting blades or other cuttinginstruments for resecting the bone and/or shaping the bone for receivingan implant, as described in commonly-owned, co-pending in U.S. patentapplication Ser. No. 11/756,057, filed on May 31, 2007, incorporatedherein by reference. The alignment guide can be placed on and conformwith the anterior/lateral surface of the tibia, for example.

Referring to FIG. 6, the alignment guide 200 can include a guidingreceptacle in the form of a planar slot 206 oriented to define apatient-specific angle β relative to the anatomic axis A for guiding ablade 500 a to form the planar cut 90. The blade 500 a can includedepth-control indicia 502 corresponding to the hinge line 94. Thealignment guide 200 can also define one or more fixation apertures 204for receiving bone fixation fasteners 250. Additional guidingreceptacles, such as guiding apertures 208, can be provided forpreparing fastener holes in the tibia 80 to receive the bone fixationfasteners 250 through the apertures 408 of the fixation plate 400. Thelocation and orientation of the planar slot 206, the apertures 204 forthe fasteners 250 and the guiding apertures 208 relative to alignmentguide 200 can be determined during the pre-operative planning stage on apatient-specific (patient customized) basis. Similarly, the planar slot206 can be oriented at a corresponding patient-specific angle φ₂relative to the medial-lateral axis B₁, as illustrated in FIG. 1A.

Referring to FIG. 8, another alignment guide 200 for open-wedgeosteotomy is illustrated. The alignment guide 200 can be placed on theanterior and/or lateral side of the proximal tibia 80, such that thethree-dimensional patient-specific engagement surface 202 of thealignment guide 200 closely conforms to the corresponding portion of thetibia 80. The plane defined by the planar slot 206 is shown in phantomat a corresponding angle β=90−φ₁ relative to the reference/anatomic axisA, as discussed above in connection with FIG. 6. A blade 500 b can beused for the plane cut through the planar slot 206 having size thatprovides automatic control of the length of the cut.

Referring to FIGS. 4 and 5, an exemplary closed-wedge high tibialosteotomy is illustrated in association with a knee joint 75 between afemur 70 and a tibia 80. First and second partial planar cuts 90 a, 90 bat corresponding selected first and second angles β₁ and β₂ relative toa reference/anatomic axis A of the knee joint 75 can be made using apatient-specific kit of the present teachings. The first and secondplanar cuts 90 a, 90 b can intersect at a hinge line 94. The first andsecond angles β₁ and β₂ of the planar cuts 90 a, 90 b relative to thereference axis A can be determined during the pre-operative planningstage of the osteotomy and in relation to the corresponding alignmentguide 200. Each of the first and second angles β₁ and β₂ iscomplementary of a corresponding angle φ₁ shown in FIG. 1A (90-β₁ and90-β₂). Similarly, the first and second cuts 90 a, 90 b can be orientedat corresponding and different angles φ₂ relative to the medial-lateralaxis B₁, as illustrated in FIG. 1A. The first and second angles β₁ andβ₂ of the planar cuts 90 a, 90 b define a bone wedge 91 of predeterminedwedge angle γ=β₁-β₂. The bone wedge 91 can be removed and thecorresponding wedge opening can be closed by bringing the surfaces ofthe first and second cuts 90 a, 90 b in contact by rotating about thehinge line 94. A first (or osteotomy-side) patient-specific fixationplate 400′ can be attached to the tibia 80 to secure the first andsecond cuts 90 a, 90 b in contact after the bone wedge 91 is removed.The first and second cuts 90 a, 90 b can also be secured by pins,sutures or other fasteners to the bone. In the fixation plate 400′ thesame reference numerals are used to indicate features having the samefunctions as in the fixation plate 400. The fixation plate 400′ caninclude a patient-specific engagement surface 406 and apertures 408 atpatient-specific positions and orientations for guiding bone fixationfasteners 250 through the apertures 408 and into the tibia 80.

Referring to FIGS. 5 and 5A, a second (or hinge-side) fixation plate400′a can be used opposite the first or osteotomy-side fixation plate400′ on the side of the osteotomy hinge. The second fixation plate 400′acan be a patient-specific fixation plate or an off-the shelfcommercially available fixation plate. The second plate 400′a can beattached to the tibia with separate fasteners. Alternatively, the samefixation fasteners 250 can extend between both the first and secondplates 400′ and 400′a. In such case, the guiding apertures 208 of thealignment guide 200′ can be used to drill guiding holes through theentire width of the tibia 80 for guiding the location of the first andsecond plates 400′ and 400′a and the common fixation fasteners 250through the tibia and through the first and second plates 400′ and 400′.

Referring to FIG. 7, a patient-specific alignment guide 200′ for aclosed-wedge osteotomy is illustrated. In alignment guide 200′ the samereference numerals are used to indicate features having the samefunctions as in alignment guide 200. The alignment guide 200′ caninclude a three-dimensional patient-specific engagement surface 202 madeto conform to a corresponding outer surface of the tibia 80 by acomputer-assisted method utilizing a 3-D image of the patient's tibia 80during the pre-operative planning stage, as discussed above. Thealignment guide 200′ can define first and second guiding receptacles inthe form of first and second planar slots 206 a, 206 b oriented atselected first and second angles β₁ and β₂ relative to areference/anatomic axis A for guiding a blade to form the planar cuts 90a, 90 b of the removable bone wedge 91. The alignment guide 200′ canalso define one or more apertures 204 receiving bone fixation fasteners250. Additional guiding receptacles, such as guiding apertures 208 canbe provided for drilling or otherwise preparing fastener holes in thetibia 80 corresponding to the apertures 408 of the fixation plate 400for securing the fixation plate 400 to the tibia 80. The location andorientation of the first and second planar slots 206 a, 206 b, theapertures 204 and the guiding apertures 208 relative to alignment guide200′ can be determined during the pre-operative planning stage on apatient-specific base. The alignment guide 200′ can be used with a blade500 a having depth indicia 502.

Referring to FIG. 9, another alignment guide 200′ for closed-wedgeosteotomy is illustrated. The alignment guide 200′ can be placed on theanterior and/or lateral side of the proximal tibia 80, such that thepatient-specific engagement surface 202 of the alignment guide 200′closely conforms to the corresponding portion of the tibia 80. Theplanes defined by the first and second planar slots 206 a, 206 b areshown in phantom at corresponding first and second angles β₁ and β₂ (notshown) relative to the reference/anatomic axis A, as discussed above inconnection with FIG. 7 and FIG. 1A. Additionally and optionally, each ofthe first and second angles β₁ and β₂ is complementary of acorresponding angle φ₁ shown in FIG. 1A (90-β₁ and 90-β₂). Similarly,the planes defined by the first and second planar slots 206 a, 206 b canbe oriented at corresponding and different angles φ₂ relative to themedial-lateral axis B₁, as illustrated in FIG. 1A.

Referring to FIGS. 10-13, another embodiment of a patient-specificalignment guide is illustrated at 600. As in the embodiments discussedabove, the patient-specific alignment guide includes a three-dimensionalpatient-specific engagement surface 602, fixation apertures 604 for bonefixation fasteners 650 and guiding apertures 608 for drilling holes inthe bone. In this embodiment, the alignment guide 600 includes a centralcylindrical through-hole 611 passing through the center of a planar slot606. The central hole 611, which has a diameter greater than the openingof the slot 606, can facilitate cutting with a blade along the slot 606through either side of the central hole 611. Referring to FIG. 11, thecentral hole 611 of the alignment guide 600 can be used to drill a hole93 in the bone 80 before the planar osteotomy cut 90 is performed at aselected patient-specific angle β, as shown in FIG. 11. Thepatient-specific guide 600 can include radiolucent markers 620, whichare visible in radiographic images and can provide directional guidanceduring the surgical procedure. Similar markers in the form of lines orpoints/spots can also be provided on the patient-specific alignmentguides 200, 200′ discussed above.

Referring to FIGS. 12 and 13, a patient-specific implantable wedge 700can be inserted through the osteotomy cut to keep the osteotomy open.Similarly to the embodiments described above, the implantable wedge 700can include a three-dimensional patient-specific surface 708 (best shownin FIG. 13), an elongated curved central portion 712 conforming to shapeof the drilled hole 93 on the opposite surfaces of the planar cut 90.The elongated central portion 712 can be cylindrical or tapered(truncated cone or conical segment). A pair of planar portions 702, 704extend radially from opposite sides of the central portion 712 from thepatient specific surface 708 to an end surface 706 and define a wedge ofangle γ. The central portion 712 can be aligned with the hole 93 andprovide a guide for centering and inserting the implantable wedge 700into the osteotomy cut 90. The central portion 712 can have greaterthickness than and protrude away from and outside the planar portions702, 704.

The various patient-specific implantable wedges 300, 700 for theopen-wedge osteotomy can be made of various biocompatible materialsincluding, for example, various metals or alloys, porous metal andporous metal alloys and bone-growth inducing materials, including ProOsteon®, commercially available from Biomet, Inc., Warsaw, Ind., with orwithout a resorbable filler material. The implantable wedges 300, 700can also be in the form of multiple-component wedges with or withoutinterlocking connecting features. An exemplary illustration of amultiple-piece implantable wedge 800 is shown in FIGS. 14A and 14B. Theimplantable wedge 800 can extend from a first surface 808 to a secondsurface 807. The first surface 808 can be optionally patient-specific.The implantable wedge 800 can include a plurality of separate components802. Two adjacent components 802 can be in contact at a common boundary804. The adjacent components 802 can also be optionally interlocked witha connecting feature 806. The connecting feature 806 can be a singlestructural connector or a plurality of structural connectors, includingtongue and groove, interdigitation, dovetail, threaded fasteners, etc.

The various fixation plates 400, 400′, 400′a can be made of similarmaterials. For open-wedge osteotomies, the fixation plate 400 can beintegral to the implantable wedge 300, modularly coupled to theimplantable wedge 300 via a connecting joint or fasteners, or directlycoupled to the bone outside the implantable wedge 300. The variousalignment guides 200, 200′, 600 can be made of any biocompatiblematerial, including, polymer, ceramic, metal or combinations thereof.

As discussed above, a surgical kit for an open-wedge or a closed-wedgehigh tibial osteotomy can be provided on a patient-specific basis. Thesurgical kit can include a patient-specific alignment guide and,optionally, a patient-specific or an off-the-self fixation plate. For anopen-wedge osteotomy, the surgical kit can include a patient-specific oran off-the-shelf implantable wedge. The patient-specific tools andimplants are customized and prepared for the specific patient during acomputer-assisted pre-operative planning stage in which the patient'sanatomy is modeled in three dimensions from two-dimensional image scans.Patient-specific or customized blades can be included to provideadjustable depth control or automatic length. Other, non-customizedblades can also be included.

The foregoing discussion discloses and describes merely exemplaryarrangements of the present teachings. Furthermore, the mixing andmatching of features, elements and/or functions between variousembodiments is expressly contemplated herein, so that one of ordinaryskill in the art would appreciate from this disclosure that features,elements and/or functions of one embodiment may be incorporated intoanother embodiment as appropriate, unless described otherwise above.Moreover, many modifications may be made to adapt a particular situationor material to the present teachings without departing from theessential scope thereof. One skilled in the art will readily recognizefrom such discussion, and from the accompanying drawings and claims,that various changes, modifications and variations can be made thereinwithout departing from the spirit and scope of the present teachings asdefined in the following claims.

What is claimed is:
 1. A surgical method comprising: attaching athree-dimensional engagement surface of a patient-specific alignmentguide to a corresponding surface of a tibia of a patient for whom thealignment guide is custom-made by computer imaging during apre-operative planning stage, the three-dimensional engagement surfaceconforming as a negative surface to the corresponding surface of thepatient's tibia; making a partial bone cut in the tibia through a planarslot of the alignment guide, the planar slot oriented at apatient-specific angle relative to an anatomic axis of the patient, theangle custom-selected during the pre-operative planning stage forcorrecting the patient's anatomy; opening the bone cut to form awedge-shaped opening in the tibia; and inserting a patient-specificimplantable wedge into the wedge-shaped opening, the implantable wedgeincluding first and second planar surfaces defining a wedge angletherebetween, the wedge angle custom-selected during pre-operativeplanning for correcting the patient's anatomy.
 2. The surgical method ofclaim 1, further comprising removably attaching a patient-specificfixation plate to the implantable wedge, the patient-specific fixationplate having a custom made surface mating as a negative surface with acorresponding surface of the patient's tibia.
 3. The surgical method ofclaim 1, wherein inserting a patient-specific implantable wedge into theopening wedge includes attaching a patient-specific fixation platemonolithically formed with the implantable wedge, the patient-specificfixation plate having a custom made surface mating as a negative surfacewith a corresponding surface of the patient's tibia.
 4. The surgicalmethod of claim 2, further comprising drilling bone apertures for bonefasteners through patient-specific apertures of the alignment guide. 5.The surgical method of claim 2, wherein the planar slot defines a depthor length dimension of the cut.
 6. The surgical method of claim 2,further comprising drilling a hole in the tibia through a centralaperture intersecting the planar slot of the patient-specific alignmentguide before making a bone cut through the planar slot.
 7. The surgicalmethod of claim 2, further comprising removably coupling thepatient-specific fixation plate to the implantable wedge with a dovetailconnection.
 8. The surgical method of claim 2, wherein the implantablewedge includes a plurality of separate components.
 9. The surgicalmethod of claim 1, further comprising drilling a guiding hole in thetibia through a central guiding aperture passing through the planarslot.
 10. The surgical method of claim 9, wherein the implantable wedgeincludes an elongated curved central portion and pairs of planarsurfaces extending radially from the central portion and defining thewedge angle therebetween, and wherein the central portion is configuredto conform to a shape of the guiding hole drilled through the centralguiding aperture of the patient-specific alignment guide.
 11. A surgicalmethod comprising: attaching a three-dimensional engagement surface of apatient-specific alignment guide to a corresponding surface of a tibiaof a patient for whom the alignment guide is custom made by computerimaging during a pre-operative planning stage, the three-dimensionalengagement surface conforming as a negative surface to the correspondingsurface of a patient's tibial bone; making a first partial planar cut inthe tibia through a first planar slot of the alignment guide, the firstplanar slot oriented at a first patient-specific angle relative to ananatomic axis of the patient, the first patient-specific anglecustom-selected for the patient during a pre-operative planning stage;making a second partial planar cut in the tibia through a second planarslot of the alignment guide, the second planar slot oriented at a secondpatient-specific angle relative to an anatomic axis of the patient, thesecond patient-specific angle custom-selected during a pre-operativeplanning stage, the first and second planar cuts meeting at an angle todefine a bone wedge having a third patient-specific angle; removing thebone wedge to form a wedge-shaped opening; and closing the wedge-shapedopening by bringing together corresponding first and second cut surfacesof the first and second planar cuts.
 12. The surgical method of claim11, further comprising attaching a three-dimensional patient-specificengagement surface of a patient-specific fixation plate over the tibiato secure the tibia after closing the wedge-shaped opening, thethree-dimensional engagement surface conforming as a negative surface tothe corresponding surface of the patient's tibia.
 13. A surgical methodcomprising: attaching a three-dimensional engagement surface of apatient-specific alignment guide to a corresponding surface of a tibiaof a patient for whom the alignment guide is custom-made by computerimaging during a pre-operative planning stage, the three-dimensionalengagement surface conforming as a negative surface to the correspondingsurface of a patient's tibial bone; drilling a hole in the tibia througha central aperture intersecting the planar slot of the patient-specificalignment guide; making a partial bone cut in the tibia through theplanar slot of the alignment guide, the planar slot oriented at apatient-specific angle relative to an anatomic axis of the patient, theangle custom-selected during the pre-operative planning stage forcorrecting the patient's anatomy; opening the bone cut to form awedge-shaped opening in the tibia; and inserting a patient-specificimplantable wedge into the wedge-shaped opening, the implantable wedgeincluding first and second planar surfaces defining a wedge angletherebetween, the wedge angle custom-selected during pre-operativeplanning for correcting the patient's anatomy.
 14. The surgical methodof claim 13, wherein the implantable wedge includes an elongated curvedcentral portion and pairs of planar surfaces extending radially from thecentral portion and defining the wedge angle therebetween, and whereinthe central portion is configured to conform to a shape of the guidinghole drilled through the central guiding aperture of thepatient-specific alignment guide.
 15. The surgical method of claim 13,further comprising removably attaching a patient-specific fixation plateto the implantable wedge, the patient-specific fixation plate having acustom made surface mating as a negative surface with a correspondingsurface of the patient's tibia.
 16. The surgical method of claim 13,wherein inserting a patient-specific implantable wedge into the openingwedge includes attaching a patient-specific fixation platemonolithically formed with the implantable wedge, the patient-specificfixation plate having a custom made surface mating as a negative surfacewith a corresponding surface of the patient's tibia.
 17. The surgicalmethod of claim 13, further comprising removably coupling thepatient-specific fixation plate to the implantable wedge with a dovetailconnection.
 18. The surgical method of claim 13, wherein the implantablewedge includes a plurality of separate components.
 19. The surgicalmethod of claim 13, further comprising drilling bone apertures for bonefasteners through patient-specific apertures of the alignment guide. 20.The surgical method of claim 13, wherein the planar slot defines a depthor length dimension of the cut.